What feature of JavaScript allows for the creation of interactive web applications?

JavaScript event handling is crucial for creating interactive web applications as it allows developers to respond to user actions dynamically. This means that when a user interacts with a webpage—such as clicking a button, hovering over an element, or pressing a key—JavaScript can be used to execute specific functions in response to these events. This interaction significantly enhances user engagement and the overall user experience, enabling features like form validation, dropdown menus, modal dialogs, and many other dynamic components that users expect from modern web applications.

In contrast, HTML structure provides the foundational framework for web pages, determining how content is organized and displayed, but does not enable interactivity by itself. CSS styling enhances the visual presentation of web content but also does not contribute to interactivity. Lastly, static content delivery refers to serving fixed content to users, which lacks any dynamic elements or responses to user actions.